The present invention relates to therapeutic and prophylactic devices, and more particularly to sleeves for applying compressive pressures against the patient's limb.
It is known that the velocity of blood flow in a patient's extremities, particularly the legs, markedly decreases during confinement of the patient. Such pooling or stasis of blood is particularly pronounced during surgery, immediately after surgery, and when the patient has been confined to bed for extended periods of time. It is also known that stasis of blood is a significant cause leading to the formation of thrombi in the patient's extremities, which may have a severe deleterious effect on the patient, including death. Additionally, in certain patients it is desirable to move fluid out of interstitial spaces in extremity tissues, in order to reduce swelling associated with edema in the extremities.
Devices have been proposed for use in increasing the velocity of blood flow through the patient's limbs and minimizing edema, such as the devices disclosed in U.S. Pat. Nos. 4,013,069 and 4,030,488, and copending application Ser. No. 749,494, filed Dec. 10, 1976 now U.S. Pat. No. 4,091,804, incorporated herein by reference. These devices comprise a compression sleeve and a controller for sequentially inflating and deflating pressure chambers in the sleeve. It is desirable that the sleeves may be readily adjusted to the size of the particular patient in order to permit use of the sleeve on patients of varying leg sizes and to facilitate application of the sleeve about the patient's limb. In addition, it is desired to prevent the application of excessive pressures against the patient's limb which could impede the flow of blood through the limb.